HPV Vaccination, Attitudes and Sequential Behaviors in Adolescent Women Study Description This proposed research is designed to examine changes in adolescent women's sexual behaviors, attitudes and perceived susceptibility to HPV and HPV-related disease in the 24 months after receipt of the HPV prophylactic vaccine and describe the natural history of HPV post vaccination in this cohort. Using risk compensation and protection generalization theories and framework for examining possible post-vaccination changes, a prospectively studied cohort of HPV vaccinated adolescent women, ages 14 to 17 years will be recruited and compared to an unvaccinated cohort of comparable young women who were intensively studied during the 7 years prior to the introduction of universal HPV immunization. Data will be gathered through yearly questionnaires and quarterly interviews with concurrent STI testing (every 3 months). The significance of the research is linked to the filling of knowledge gaps that cannot be otherwise ethically addressed. If successful, the research can inform policy, public health efforts and clinical procedures needed to maximize benefits and reduce potential unintended negative consequences of the universal HPV immunization among adolescent and young adult women.